1. Field of the Invention
The present invention relates to an assembling tool, and in particular to an alignment tool for facilitating the attachment or detachment of a clutch.
2. Description of the Prior Art
A clutch of a motorcycle or an automobile is mounted between an engine and a transmission box, whereby the power output by the engine is transmitted to the transmission box via a crankshaft. The clutch is provided therein with a clutch disc. The clutch disc is gradually worn down by friction generated between a flywheel and a pressure plate in the clutch, so that the clutch disc has to be replaced periodically. Traditionally, the replacement of the clutch disc is carried out by the following steps: (1) detaching the engine from the chassis; (2) detaching the transmission box from the chassis; (3) detaching the clutch cover from the flywheel to thereby remove the clutch disc from the clutch; (4) replacing the clutch disc with a new one; (5) clamping the new clutch disc between a frictional surface of the flywheel and a surface of the pressure plate, putting the clutch cover on the flywheel, and aligning the axial hole of the clutch disc with the center of the flywheel (i.e. the center of the crankshaft); (6) mounting the clutch cover on the flywheel; (7) keeping the axial hole of the clutch consistent with the center of the flywheel, mounting the transmission box into the engine; and (8) mounting the engine to the chassis.
In the above-mentioned step (5), it is not easy to align the axial center of the clutch disc with the center of the flywheel. Thus, a special assembling took is needed. Please refer to FIG. 1. A conventional assembling tool 90 is formed at its front end with a front rod portion 91 and a middle rod portion 92. The front rod portion 91 and the middle rod portion 92 are of different diameters. In use, the front rod portion 91 is disposed through a flywheel 81 and then inserted into a shaft hole 821 of a crankshaft 82. The middle rod portion 92 is disposed through a shaft hole 831 of a clutch disc 83. In this way, the flywheel 81, the crankshaft 82 and the clutch disc 83 are positioned along the same axial center. However, in various kinds of motorcycles or automobiles, the shaft hole 831 of the clutch disc 83 and the shaft hole 821 of the crankshaft 82 are different in diameter. As a result, various kinds of assembling tools 90 have to be present in a garage, which makes it inconvenient to use and affects the assembling efficiency and quality of the clutch.
EP191550A2 discloses a conventional assembling tool having an expanding mechanism at its middle section for adjusting the outer diameter of the assembling tool. The expanding mechanism is configured to abut against the shaft hole of the clutch disc. The expanding mechanism is constituted of an operating rod and a conical sleeve. The front end of the operating rod is provided with a claw portion of a larger diameter. A plurality of slots extends from an end edge of the claw portion to the middle section of the other end of the operating rod. The inner edge of the claw portion is formed with an inner conical surface corresponding to the outer edge of the conical sleeve, whereby the rear end of the conical sleeve can be assembled in the claw portion. Further, the front end of this conventional assembling tool is provided with positioning claws capable of generating a radial expansion or retraction for abutting against the shaft hole of the crankshaft. The positioning claws are constituted of three claws combined together with a plastic sheath. The positioning claws are positioned to correspond to the inner edge of the conical sleeve and formed into an inner slope to correspond to its outer conical surface. In assembly, the front end of the conical sleeve is exactly disposed in the positioning claws.
With this structure, when the operating rod is pushed by related component provided at its rear end, the front end and the rear end of the conical sleeve are simultaneously located in the positioning claws and the expanding claws. The provision of the slope allows the positioning claws and the expanding claws to generate a radial expansion, thereby contacting the shaft holes of the crankshaft and the clutch disc. However, such a structure has the following problems:
(I) The operating rod is a rigid body, and only the expanding claws and the front section of the operating rod are provided with slots. If the shaft hole of the clutch disc is large, a greater force is needed for expanding the large-diameter expanding claws. Further, the repeated expansion and retraction of the expanding claws may cause fatigue of the rigid operating rod. Since the expansion of the expanding claws is caused by the forward abutment of the conical sleeve against the positioning claws, such a process may be carried out in a less smooth and steady manner.
(II) The positioning claws are exposed to the outside, so that the plastic sheath is used to combine the positioning claws together. However, the plastic sheath is brought into frictional contact with the components in the clutch for a long period of time, so that the plastic sheath may become worn and broken. Further, the repeated expansion of these claws may cause elastic fatigue in the plastic sheath.
In view of the above, the present inventor proposes a novel and reasonable structure based on his expert experience and delicate researches.